JP2007294901A - Organic luminous device - Google Patents

Organic luminous device Download PDF

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JP2007294901A
JP2007294901A JP2007068479A JP2007068479A JP2007294901A JP 2007294901 A JP2007294901 A JP 2007294901A JP 2007068479 A JP2007068479 A JP 2007068479A JP 2007068479 A JP2007068479 A JP 2007068479A JP 2007294901 A JP2007294901 A JP 2007294901A
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light emitting
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JP2007294901A5 (en
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Kiyoshi Miura
聖志 三浦
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Canon Inc
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Canon Inc
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Priority to US11/692,545 priority patent/US7605532B2/en
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/17—Carrier injection layers
    • H10K50/171—Electron injection layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/14—Carrier transporting layers
    • H10K50/16—Electron transporting layers
    • H10K50/165—Electron transporting layers comprising dopants

Abstract

<P>PROBLEM TO BE SOLVED: To improve driving endurance characteristics and obtain high light fetch efficiency in an organic luminous device where an electron implantation dopant material is doped into an electron transfer material. <P>SOLUTION: The organic luminous device has a luminous layer 12 and an electron implantation transfer layer 16 that are sandwiched between a pair of electrodes including an anode 14 and a cathode 17. For the electron implantation transfer layer 16, doping concentration is prepared to be each small, big, and small regions of 16a, 16b, and 16c in order from the side of the luminous layer 12 in the film thickness direction, when the electron implantation dopant material is doped into the electron transfer material. Further, it is desirable that the doping concentration is set at a bigger one in a region 16d that contacts the cathode 17 of the electron implantation transfer layer 16. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

本発明は、有機発光素子及びその製造方法に関し、特に、フラットパネルディスプレイ、プロジェクションディスプレイ、プリンター等に用いられる多色発光素子として利用される有機発光素子及びその製造方法に関するものである。   The present invention relates to an organic light-emitting device and a method for manufacturing the same, and more particularly to an organic light-emitting device used as a multicolor light-emitting device used in flat panel displays, projection displays, printers, and the like, and a method for manufacturing the same.

近年、フラットパネル対応の自発光型デバイスが注目されている。自発光型デバイスとしては、プラズマ発光表示素子、フィールドエミッション素子、有機発光素子（エレクトロルミネセンス（ＥＬ）素子）等がある。   In recent years, self-luminous devices compatible with flat panels have attracted attention. Examples of the self-luminous device include a plasma light-emitting display element, a field emission element, and an organic light-emitting element (electroluminescence (EL) element).

特に有機発光素子に関しては、１９８７年にＴ．Ｗ．Ｔａｎｇらにより蛍光性金属キレート錯体とジアミン系分子の薄膜を積層した構造を利用して、低電圧ＤＣ駆動で高輝度な発光が得られることが実証され、研究開発が精力的に進められている。   In particular, regarding organic light emitting devices, T.W. W. Tang et al. Have demonstrated that high-luminance light emission can be obtained with low-voltage DC drive using a structure in which fluorescent metal chelate complexes and diamine-based molecular thin films are stacked, and research and development are underway energetically. .

有機発光素子の研究開発課題として、駆動電圧の低減、光取り出し効率の向上、駆動劣化特性の改善等を挙げることができる。従来、これらの課題を解決するために、有機化合物層への電子注入材料のドーピングを行う技術が知られている。   Research and development issues for organic light emitting devices include reduction of drive voltage, improvement of light extraction efficiency, improvement of drive deterioration characteristics, and the like. Conventionally, in order to solve these problems, a technique for doping an electron injection material into an organic compound layer is known.

すなわち、電子注入輸送層として、電子輸送材料と、アルカリメタル、あるいはアルカリ塩又はアルカリ酸化物とを用いることで、駆動電圧の低減を図る技術が知られている（特許文献１、特許文献２参照）。また、陰極に近い側では電子注入材料の割合が多く、陰極から離れるに従って電子輸送材料の割合が多くなるよう濃度勾配を設けることにより、駆動電圧の低減を図る技術が知られている（特許文献３参照）。また、電子注入輸送層として、取り扱いの容易な炭酸セシウムと電子輸送材料の混合層とを用い、そのドープ濃度を８重量％以下とすることで、経時的な劣化を抑制する技術が知られている（特許文献４参照）。   That is, a technique for reducing the driving voltage by using an electron transport material and an alkali metal, an alkali salt, or an alkali oxide as an electron injecting and transporting layer is known (see Patent Document 1 and Patent Document 2). ). In addition, a technique for reducing the driving voltage by providing a concentration gradient so that the ratio of the electron injection material is large on the side close to the cathode and the ratio of the electron transport material is increased as the distance from the cathode is increased is known (Patent Document). 3). In addition, a technique for suppressing deterioration over time by using a mixed layer of cesium carbonate and an electron transport material, which is easy to handle, and having a dope concentration of 8% by weight or less is known. (See Patent Document 4).

特開平１０−２７０１７１号公報JP-A-10-270171 特開平１０−２７０１７２号公報JP-A-10-270172 特開２００２−３１３５８３号公報JP 2002-313583 A 特開２００５−６３９１０号公報JP 2005-63910 A

しかし、本発明者らが検討を行ったところ、電子輸送材料に対してアルカリメタル或いはその塩又は酸化物等の電子注入ドーパント材料を高濃度でドープすることは、駆動電圧を低減する効果はあるものの、光取り出し効率の低下を招くことが明らかになった。   However, as a result of studies by the present inventors, doping the electron transport material with an electron injection dopant material such as an alkali metal or a salt or oxide thereof at a high concentration has an effect of reducing the driving voltage. However, it became clear that the light extraction efficiency was lowered.

本発明は、上述した課題に鑑みなされたものであり、電子輸送材料に対して電子注入ドーパント材料がドープされた有機発光素子において、駆動耐久特性を向上するとともに、高い光取り出し効率を得ることが可能な技術を提供することを目的としている。   The present invention has been made in view of the above-described problems, and in an organic light-emitting device in which an electron-injecting dopant material is doped with respect to an electron-transporting material, driving durability characteristics can be improved and high light extraction efficiency can be obtained. It aims to provide possible technology.

本発明の有機発光素子は、上述した目的を達成するため、以下の特徴点を有している。すなわち、本発明の有機発光素子は、互いに対向して配置されている陽極および陰極と、前記陽極と前記陰極の間に形成されている発光層と、前記陰極と前記発光層の間に形成されており、前記陰極および前記発光層に接している電子注入輸送層と、を有し、
前記電子注入輸送層は、電子輸送材料と、電子注入ドーパント材料としてアルカリ金属あるいはアルカリ金属化合物、を含む有機発光素子であって、
前記電子注入輸送層は、前記発光層側から順に、前記電子注入ドーパント濃度の異なる第１領域、第２領域、第３領域、を有しており、
前記第２領域の前記電子注入ドーパント材料の濃度は、前記第１領域および前記第３領域の前記電子注入ドーパント材料の濃度よりも高いことを特徴とする。 The organic light-emitting device of the present invention has the following characteristics in order to achieve the above-described object. That is, the organic light-emitting device of the present invention is formed with an anode and a cathode disposed opposite to each other, a light-emitting layer formed between the anode and the cathode, and between the cathode and the light-emitting layer. An electron injecting and transporting layer in contact with the cathode and the light emitting layer, and
The electron injecting and transporting layer is an organic light emitting device comprising an electron transporting material and an alkali metal or an alkali metal compound as an electron injecting dopant material,
The electron injection transport layer has, in order from the light emitting layer side, a first region, a second region, and a third region having different electron injection dopant concentrations,
The concentration of the electron injection dopant material in the second region is higher than the concentration of the electron injection dopant material in the first region and the third region.

本発明の有機発光素子によれば、光取り出し効率の低下を招くことなく、駆動耐久特性を向上させることができる。   According to the organic light emitting device of the present invention, it is possible to improve driving durability characteristics without causing a decrease in light extraction efficiency.

以下、本発明の有機発光素子の実施形態について説明する。なお、本発明の有機発光素子は、以下の実施形態に限定されるものではない。   Hereinafter, embodiments of the organic light emitting device of the present invention will be described. The organic light emitting device of the present invention is not limited to the following embodiment.

本発明の実施形態に係る有機発光素子は、互いに対向して配置されている陽極および陰極と、陽極と陰極の間に形成されている発光層と、陰極と発光層の間に形成されており、陰極および発光層に接している電子注入輸送層と、を有する。電子注入層は、電子輸送材料と、電子注入ドーパント材料としてアルカリ金属あるいはアルカリ金属化合物と、を含んでおり、発光層側から順に、電子注入ドーパント濃度の異なる第１領域、第２領域、第３領域、を有している。そして、第２領域の前記電子注入ドーパント材料の濃度は、前記第１領域および前記第３領域の前記電子注入ドーパント材料の濃度よりも高い。   An organic light-emitting device according to an embodiment of the present invention is formed between an anode and a cathode disposed opposite to each other, a light-emitting layer formed between the anode and the cathode, and between the cathode and the light-emitting layer. And an electron injecting and transporting layer in contact with the cathode and the light emitting layer. The electron injection layer includes an electron transport material and an alkali metal or an alkali metal compound as an electron injection dopant material. The first region, the second region, and the third region having different electron injection dopant concentrations in order from the light emitting layer side. Area. The concentration of the electron injection dopant material in the second region is higher than the concentration of the electron injection dopant material in the first region and the third region.

この点、前記特許文献３に記載された技術では、電子注入輸送層中で電子注入ドーパント材料の濃度が単調減少している。これに対して、本発明の有機発光素子では、電子注入輸送層中における電子注入ドーパント材料の濃度が、膜厚方向で発光層側から順に小、大、小というように濃度の異なる３つの領域を有している。そして、この構成の差異により、本発明の有機発光素子では、光取り出し効率の向上、駆動劣化の抑制を実現することができる。   In this regard, in the technique described in Patent Document 3, the concentration of the electron injection dopant material monotonously decreases in the electron injection transport layer. In contrast, in the organic light-emitting device of the present invention, the concentration of the electron-injecting dopant material in the electron-injecting and transporting layer is three regions having different concentrations such as small, large, and small in order from the light-emitting layer side in the thickness direction have. Due to this difference in configuration, the organic light emitting device of the present invention can realize improvement in light extraction efficiency and suppression of drive deterioration.

次に、図面を参照して、本発明の実施形態に係る有機発光素子について説明する。図１は、本発明の実施形態に係る有機発光素子の概略構成を示す縦断面図である。   Next, an organic light-emitting device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing a schematic configuration of an organic light emitting device according to an embodiment of the present invention.

図１に示すように、本発明の実施形態に係る有機発光素子１０は、基板１５上に陽極１４が形成され、その上に有機化合物層として、ホール輸送層１３、発光層１２、電子注入輸送層１６が形成され、さらにその上に陰極１７が形成された構成となっている。   As shown in FIG. 1, an organic light emitting device 10 according to an embodiment of the present invention has an anode 14 formed on a substrate 15, and a hole transport layer 13, a light emitting layer 12, an electron injection transport as an organic compound layer thereon. The layer 16 is formed, and the cathode 17 is further formed thereon.

以下、有機発光素子１０を構成する各層の材料について具体的に説明する。   Hereinafter, the material of each layer which comprises the organic light emitting element 10 is demonstrated concretely.

基板１５の材料としては、各種のガラス基板や、ｐｏｌｙ−ＳｉでＴＦＴ等の駆動回路を形成したガラス基板、シリコンウエハー上に駆動回路を設けたもの等を挙げることができる。また、基板１５と反対側から光を取り出す場合には、基板１５は透明でなくてもよいが、基板１５側から光を取り出す場合には、基板１５は透明であることが好ましい。   Examples of the material of the substrate 15 include various glass substrates, glass substrates in which driving circuits such as TFTs are formed with poly-Si, and those in which driving circuits are provided on a silicon wafer. Moreover, when taking out light from the opposite side to the board | substrate 15, the board | substrate 15 may not be transparent, but when taking out light from the board | substrate 15 side, it is preferable that the board | substrate 15 is transparent.

陽極１４の材料としては、仕事関数の大きな導電性材料を選択することが好ましい。さらに、基板１５と反対側から光を取り出す場合には、反射率の高い金属材料を選択することが好ましい。例えば、Ｃｒ、Ｐｔ、Ａｇ、Ａｕ等の金属材料、及びこれらの金属材料を含む合金等が好適に用いられる。また、高反射率の金属材料上に、透明導電性材料の薄膜を形成したものを用いてもよい。また、透明導電性材料としてＩＴＯ等のように仕事関数の大きな材料を用いる場合には、必ずしも仕事関数の大きな金属材料を選択する必要はない。   As a material for the anode 14, it is preferable to select a conductive material having a large work function. Furthermore, when light is extracted from the side opposite to the substrate 15, it is preferable to select a metal material having a high reflectance. For example, metal materials such as Cr, Pt, Ag, and Au, and alloys containing these metal materials are preferably used. Moreover, you may use what formed the thin film of the transparent conductive material on the metal material of high reflectance. Further, when a material having a large work function such as ITO is used as the transparent conductive material, it is not always necessary to select a metal material having a large work function.

基板１５と反対側から光を取り出す場合には、陰極１７が透明であることが好ましく、陰極１７の材料として、例えばＩＴＯ等の透明導性電材料を用いることができる。また、金属材料を１ｎｍから１０ｎｍ程度の薄膜で形成し、透光性のある陰極１７としてもよい。さらに、半透光性を有する陰極１７を用いることにより、光の干渉効果を利用して、光の外部取り出し効率の向上を図るとともに、色純度の向上を図ることも可能である。   When extracting light from the side opposite to the substrate 15, the cathode 17 is preferably transparent, and a transparent conductive material such as ITO can be used as the material of the cathode 17. Alternatively, a light-transmitting cathode 17 may be formed by forming a metal material as a thin film having a thickness of about 1 nm to 10 nm. Further, by using the semi-transparent cathode 17, it is possible to improve the light extraction efficiency and improve the color purity by utilizing the light interference effect.

ホール輸送層１３を形成する正孔輸送材料としては、トリフェニルジアミン誘導体、オキサジアゾール誘導体、ポリフィリン誘導体、スチルベン誘導体等の低分子化合物等を挙げることができるが、これらの材料に限定されるものではない。   Examples of the hole transport material forming the hole transport layer 13 include low molecular compounds such as a triphenyldiamine derivative, an oxadiazole derivative, a porphyrin derivative, and a stilbene derivative, but are limited to these materials. is not.

発光層１２の材料としては、単一の材料で所望の発光を得る材料、あるいはホスト材料にゲスト材料をドープしたものが用いられる。すなわち、ホスト材料及びゲスト材料を同時に真空蒸着し、それぞれの蒸着レートを調整することで、任意のドープ濃度とした発光層１２を得ることができる。また、発光層１２を形成する際に、適時、第二、第三のドーパント材料をドープしてもよい。   As the material of the light emitting layer 12, a material that obtains desired light emission with a single material or a host material doped with a guest material is used. That is, the light-emitting layer 12 having an arbitrary dope concentration can be obtained by simultaneously vacuum-depositing the host material and the guest material and adjusting the respective deposition rates. Further, when forming the light emitting layer 12, the second and third dopant materials may be doped as appropriate.

電子注入輸送層１６を形成する電子輸送材料としては、アルミキノリノール誘導体、オキサジアゾール誘導体、トリアゾール誘導体、フェニルキノキサリン誘導体、シロール誘導体等を挙げることができるが、これらの材料に限定されるものではない。   Examples of the electron transport material for forming the electron injection / transport layer 16 include an aluminum quinolinol derivative, an oxadiazole derivative, a triazole derivative, a phenylquinoxaline derivative, and a silole derivative, but are not limited to these materials. .

電子注入輸送層１６は、電子注入ドーパント材料のドープ濃度に応じて、発光層１２側から順に、膜厚方向で３つの領域１６ａ（第１領域）、１６ｂ（第２領域）、１６ｃ（第３領域）、が形成されている。各領域では、それぞれ所望の濃度で、電子輸送材料中に電子注入ドーパント材料であるアルカリ金属あるいはアルカリ金属化合物がドープされている。   The electron injecting and transporting layer 16 has three regions 16a (first region), 16b (second region), and 16c (third region) in the thickness direction in order from the light emitting layer 12 side according to the doping concentration of the electron injecting dopant material. Region), is formed. In each region, the electron transport material is doped with an alkali metal or an alkali metal compound as an electron injection dopant material at a desired concentration.

ここで、領域１６ａのドープ濃度は、電子注入輸送層１６の全体における平均ドープ濃度よりも小さく設定されている。具体的には、領域１６ａにおけるドープ濃度は、１．０重量％未満であることが好ましく、０．１重量％以下であることがさらに好ましく、０．０１重量％以下であることがさらに一層好ましい。   Here, the doping concentration of the region 16 a is set to be lower than the average doping concentration in the entire electron injecting and transporting layer 16. Specifically, the dope concentration in the region 16a is preferably less than 1.0% by weight, more preferably 0.1% by weight or less, and still more preferably 0.01% by weight or less. .

また、領域１６ｂのドープ濃度は、電子注入輸送層１６の全体における平均ドープ濃度よりも大きく設定されている。具体的には、領域１６ｂにおけるドープ濃度は、４重量％以上６重量％以下であることが好ましい。尚、領域１６ｂの厚みは５ｎｍ以上２０ｎｍ以下が好ましい。   Further, the doping concentration of the region 16b is set to be higher than the average doping concentration in the entire electron injecting and transporting layer 16. Specifically, the dope concentration in the region 16b is preferably 4% by weight or more and 6% by weight or less. The thickness of the region 16b is preferably 5 nm or more and 20 nm or less.

また、領域１６ｃのドープ濃度は、電子注入輸送層１６の全体における平均ドープ濃度よりも小さく設定されている。具体的には、領域１６ｃにおけるドープ濃度は、１．０重量％以下であることが好ましく、この範囲において０．１重量％以上であることがさらに好ましい。   Further, the doping concentration of the region 16 c is set to be lower than the average doping concentration in the entire electron injecting and transporting layer 16. Specifically, the dope concentration in the region 16c is preferably 1.0% by weight or less, and more preferably 0.1% by weight or more in this range.

このように、本実施形態の電子注入輸送層１６は、膜厚方向の中央の領域１６ｂが発光層側の領域１６ａ及び陰極側の領域１６ｃと比較してドープ濃度が大きくなるように、電子輸送材料に電子注入ドーパント材料がドープされている。すなわち、電子注入輸送層１６を構成する膜厚方向の各領域１６ａ，１６ｂ，１６ｃでは、発光層１２側から順に、ドープ濃度が小、大、小となっている。   Thus, the electron injecting and transporting layer 16 of this embodiment has an electron transporting property such that the central region 16b in the film thickness direction has a higher doping concentration than the region 16a on the light emitting layer side and the region 16c on the cathode side. The material is doped with an electron injection dopant material. That is, in each region 16a, 16b, 16c in the film thickness direction constituting the electron injecting and transporting layer 16, the dope concentrations are small, large, and small in order from the light emitting layer 12 side.

このように各領域の電子注入ドーパント材料の濃度を異ならせることによって、光取り出し効率の低下を招くことなく駆動耐久特性を向上させることができる。駆動耐久特性を向上させるためには１６ｂ（第２領域）の濃度を高くする必要があることが分かったが、１６ａ（第１領域）、１６ｃ（第３領域）の濃度を同様に高くしても駆動耐久特性を向上させることはできなかった。一方、電子注入輸送層中の電子注入ドーパント材料の濃度を高くすると、発光層１２で発光する光を外部に取り出す光取り出し効率が低下してしまうことが分かった。そのため、濃度を高くしても駆動耐久特性の向上との関係が見られない１６ａ及び１６ｃの濃度を低くすることが好ましい。したがって、本実施形態の有機発光素子の電子注入層は、１６ｂ（第２領域）の電子注入ドーパント材料の濃度を高めつつ、１６ａ（第１領域）、１６ｃ（第３領域）の電子注入ドーパント材料の濃度を低くすることが好ましい。このようにすることによって、駆動耐久特性と、光取り出し効率の両方を満足する有機発光素子を得ることができる。   Thus, by varying the concentration of the electron injection dopant material in each region, it is possible to improve the driving durability characteristics without causing a decrease in light extraction efficiency. In order to improve the driving durability characteristics, it has been found that the concentration of 16b (second region) needs to be increased, but the concentration of 16a (first region) and 16c (third region) is similarly increased. However, the driving durability characteristics could not be improved. On the other hand, it was found that when the concentration of the electron injection dopant material in the electron injection transport layer is increased, the light extraction efficiency for extracting light emitted from the light emitting layer 12 to the outside is lowered. For this reason, it is preferable to lower the concentrations of 16a and 16c, which do not show a relationship with improvement in driving durability characteristics even when the concentration is increased. Therefore, the electron injection layer of the organic light emitting device of the present embodiment increases the concentration of the electron injection dopant material of 16b (second region), while increasing the concentration of the electron injection dopant material of 16a (first region) and 16c (third region). It is preferable to reduce the concentration of. By doing in this way, the organic light emitting element which satisfies both a drive durability characteristic and light extraction efficiency can be obtained.

さらに、本発明にかかる有機発光素子の電子注入層は、図２に示すように１６ｃと電子注入ドーパント材料の濃度が異なる１６ｄ（第４領域）が、１６ｃの陰極側に設けられていることが好ましい。１６ｄの濃度を１６ｃの濃度よりも高めることによって、陰極１７から電子注入輸送層１６への電子注入障壁を低減することができるため、駆動電圧を低減することができる。   Furthermore, as shown in FIG. 2, the electron injection layer of the organic light emitting device according to the present invention is provided with 16d (fourth region) having a different concentration of the electron injection dopant material on the cathode side of 16c. preferable. By increasing the concentration of 16d higher than the concentration of 16c, the electron injection barrier from the cathode 17 to the electron injection transport layer 16 can be reduced, so that the driving voltage can be reduced.

領域１６ｄのドープ濃度は、電子注入輸送層１６の全体における平均ドープ濃度よりも大きく設定されている。具体的には、領域１６ｄにおけるドープ濃度は、４重量％以上６．０重量％以下であることが好ましい。   The doping concentration of the region 16 d is set to be higher than the average doping concentration in the entire electron injecting and transporting layer 16. Specifically, the doping concentration in the region 16d is preferably 4% by weight or more and 6.0% by weight or less.

このように、図２に示す実施形態の電子注入輸送層１６は、膜厚方向の中央の領域１６ｂが発光層側の領域１６ａ及び陰極側の領域１６ｃと比較してドープ濃度が大きくなるように、電子輸送材料に電子注入ドーパント材料がドープされている。また、電子注入輸送層１６を構成する陰極側領域１６ｃのさらに陰極１７側に陰極１７に接する領域１６ｄが存在し、この領域１６ｄにおけるドープ濃度は、領域１６ｃよりも大きくなっている。したがって、電子注入輸送層１６を全体としてみると、膜厚方向の各領域１６ａ，１６ｂ，１６ｃ，１６ｄでは、発光層１２側から順にドープ濃度が小、大、小、大となっている。   As described above, the electron injecting and transporting layer 16 of the embodiment shown in FIG. 2 has a doping concentration higher in the central region 16b in the film thickness direction than in the region 16a on the light emitting layer side and the region 16c on the cathode side. The electron transport material is doped with an electron injection dopant material. Further, a region 16d in contact with the cathode 17 is present further on the cathode 17 side of the cathode side region 16c constituting the electron injection / transport layer 16, and the doping concentration in this region 16d is higher than that in the region 16c. Therefore, when the electron injecting and transporting layer 16 is viewed as a whole, the doping concentration is sequentially from the light emitting layer 12 side in the respective regions 16a, 16b, 16c, and 16d in the film thickness direction.

各領域における電子注入ドーパント材料のドープ濃度を上述した数値範囲とすることにより、光取り出し効率の低下を招くことなく駆動耐久特性を向上させることができるとともに、駆動電圧を低減することができる。   By setting the doping concentration of the electron-injecting dopant material in each region within the above-described numerical range, it is possible to improve driving durability characteristics and reduce driving voltage without causing a decrease in light extraction efficiency.

以上、本発明にかかる有機発光素子の構成について説明したが、電子注入輸送層の各領域の電子注入ドーパント材料の濃度は、膜厚方向で一定の濃度になっていなくてもよい。つまり、隣接する領域の境界付近の電子注入ドーパント材料の濃度は、それぞれの領域の電子注入ドーパント材料の濃度の間の濃度となっており、濃度勾配を持っていてもよい。   Although the configuration of the organic light emitting device according to the present invention has been described above, the concentration of the electron injection dopant material in each region of the electron injection transport layer may not be a constant concentration in the film thickness direction. That is, the concentration of the electron injection dopant material in the vicinity of the boundary between adjacent regions is a concentration between the concentration of the electron injection dopant material in each region, and may have a concentration gradient.

ここで、本発明で用いている、電子注入輸送層の効果について説明する。特許文献３で開示されている様に、アルカリ金属、或いはアルカリ金属化合物と電子輸送材料を共蒸着した層は、電極からの電子注入性を改善させることができると共に、その抵抗値も非常に低いことが知られている。この効果はアルカリ金属及びアルカリ金属化合物と電子輸送材料との相互作用による。   Here, the effect of the electron injecting and transporting layer used in the present invention will be described. As disclosed in Patent Document 3, a layer obtained by co-evaporation of an alkali metal or an alkali metal compound and an electron transport material can improve the electron injectability from the electrode and has a very low resistance value. It is known. This effect is due to the interaction between the alkali metal and the alkali metal compound and the electron transport material.

ＩＴＯ等のように仕事関数の高い電極から電子を注入する場合には出来るだけドープ濃度が高い方が駆動電圧を低減できる。一方、電子注入層内の輸送特性は濃度依存が少なく、比較的低濃度でも良好な輸送特性を得ることが出来る。   In the case where electrons are injected from an electrode having a high work function such as ITO, the driving voltage can be reduced when the doping concentration is as high as possible. On the other hand, the transport properties in the electron injection layer are less dependent on concentration, and good transport properties can be obtained even at relatively low concentrations.

一方このような電子注入輸送層は、その相互作用に起因して、光学吸収が増加し、その量はドープ濃度と共に増加するという性質がある。よって発光取り出し効率を向上させるには、出来るだけ高濃度のドープ領域を少なくした方が良い。   On the other hand, such an electron injecting and transporting layer has the property that the optical absorption increases due to the interaction, and the amount thereof increases with the doping concentration. Therefore, in order to improve the light emission extraction efficiency, it is better to reduce the concentration region as high as possible.

また本発明で得られる、耐久特性が向上する効果については、詳細には明らかになっていないが、電子輸送材料にアルカリ金属或いはアルカリ金属化合物をドープすることにより、発光層と電子注入輸送層との物理的接合が変化することによると推定される。電子注入輸送層におけるこれらのドープ濃度を発光層側より小大とすることにより、発光層への電子注入、或いは発光層、電子注入輸送層界面における正孔の振る舞いが変化し耐久特性が向上したもと考えられる。   In addition, the effect of improving durability characteristics obtained in the present invention is not clarified in detail, but by doping an electron transport material with an alkali metal or an alkali metal compound, a light emitting layer, an electron injection transport layer, It is presumed that the physical junction of the material changes. By making these doping concentrations in the electron injecting and transporting layer smaller than those on the light emitting layer side, the electron injection into the light emitting layer or the behavior of holes at the interface between the light emitting layer and the electron injecting and transporting layer was changed, and the durability characteristics were improved. Originally considered.

これらの効果はアルカリ金属或いはアルカリ金属化合物と電子輸送材料の相互作用により発現するものであり、セシウム化合物だけでなく、ルビジウム、カリウム、ナトリウム、リチウム及びその化合物でもその効果が期待できる。特にセシウム化合物ではその電子供与性の高さより最も効果が大きい。   These effects are manifested by the interaction between the alkali metal or alkali metal compound and the electron transport material, and the effect can be expected not only with the cesium compound but also with rubidium, potassium, sodium, lithium, and compounds thereof. In particular, the cesium compound is most effective than its electron donating property.

本実施形態で用いる陰極、陽極及び有機化合物層の形成方法は、特に限定されるものではない。例えば、有機材料の場合には、電解重合法、キャスティング法、スピンコート法、浸漬コート法、スクリーン印刷法、マイクロモールド法、マイクロコンタクトプリンティング法、ロール塗布法、インクジェット法、ＬＢ法等を用いることができる。また、用いる材料に応じて、真空蒸着法、ＣＶＤ法、電子ビーム蒸着法、抵抗加熱蒸着法、スパッタ法等も、陰極、陽極及び有機化合物層の有効な形成方法となる。また、陰極、陽極及び有機化合物層は、フォトリソグラフおよびエッチング処理により所望の形状にパターニングすることができる。その他、ソフトリソグラフ、インクジェット法も有効なパターニング方法である。   The formation method of the cathode, anode, and organic compound layer used in the present embodiment is not particularly limited. For example, in the case of an organic material, an electrolytic polymerization method, a casting method, a spin coating method, a dip coating method, a screen printing method, a micro mold method, a micro contact printing method, a roll coating method, an ink jet method, an LB method, or the like is used. Can do. Depending on the material used, a vacuum deposition method, a CVD method, an electron beam deposition method, a resistance heating deposition method, a sputtering method, and the like are also effective methods for forming the cathode, the anode, and the organic compound layer. Further, the cathode, the anode and the organic compound layer can be patterned into a desired shape by photolithography and etching treatment. In addition, soft lithography and ink jet methods are also effective patterning methods.

本実施形態で用いる陰極、陽極及び有機化合物層の膜厚は特に限定はされないが、０．１ｎｍ乃至１０μｍの範囲が好ましい。   The thickness of the cathode, anode and organic compound layer used in the present embodiment is not particularly limited, but is preferably in the range of 0.1 nm to 10 μm.

また、本実施形態において得られる有機発光素子を面内に複数配置して、ディスプレイ等の情報表示部に用いることができる。ディスプレイのサイズは特に制限されないが、例えば、１インチから３０インチまでの大きさであることが好ましい。画素数も特に制限はない。例えばＱＶＧＡ（３２０×２４０画素）、ＶＧＡ（６４０×４８０画素）、ＸＧＡ（１０２４×７６８画素）、ＳＸＧＡ（１２８０×１０２４画素）、ＵＸＧＡ（１６００×１２００画素）、ＱＸＧＡ（２０４８×１５３６画素）とすることができる。また、ディスプレイは、カラー表示できることが好ましい。この場合、赤、青、緑の発光素子を独立に配列させることで表示する方法、またはカラーフィルターを用いる方法のいずれを用いてもよい。また、ディスプレイの駆動方式としては、単純マトリックス方式、またはアクティブマトリックス方式を用いることができる。   In addition, a plurality of organic light emitting elements obtained in the present embodiment can be arranged in the plane and used for an information display unit such as a display. The size of the display is not particularly limited, but is preferably 1 inch to 30 inches, for example. The number of pixels is not particularly limited. For example, QVGA (320 × 240 pixels), VGA (640 × 480 pixels), XGA (1024 × 768 pixels), SXGA (1280 × 1024 pixels), UXGA (1600 × 1200 pixels), and QXGA (2048 × 1536 pixels). be able to. The display is preferably capable of color display. In this case, any of a method of displaying by arranging red, blue, and green light emitting elements independently or a method of using a color filter may be used. As a display driving method, a simple matrix method or an active matrix method can be used.

また、有機発光素子を空気中の水分、酸素等から遮断するために、有機発光素子上にキャップを設けることが好ましい。この際、基板の膜面側から光を取り出す場合には、キャップの材料として透光性を有する部材を用いることが好ましく、例えばガラス等が用いられる。また、キャップと有機発光素子との間に空隙を設け、乾燥剤等を配置してもよい。   Moreover, it is preferable to provide a cap on the organic light emitting element in order to shield the organic light emitting element from moisture, oxygen, etc. in the air. At this time, when light is extracted from the film surface side of the substrate, it is preferable to use a light-transmitting member as the material of the cap, for example, glass or the like. Moreover, a space | gap may be provided between a cap and an organic light emitting element, and a desiccant etc. may be arrange | positioned.

また、ＳｉＮ、ＳｉＯ等の無機材料や、高分子材料等の膜を有機発光素子上に配置して外気と遮断してもよい。   Alternatively, an inorganic material such as SiN or SiO, or a film made of a polymer material or the like may be disposed on the organic light emitting element to block the outside air.

以下、具体的な実施例を用いて、本発明の有機発光素子についてさらに詳細に説明する。なお、本発明の有機発光素子は、以下の実施例に限定されるものではない。   Hereinafter, the organic light-emitting device of the present invention will be described in more detail using specific examples. The organic light emitting device of the present invention is not limited to the following examples.

＜実施例１及び実施例２、比較例１乃至比較例４＞
上述したように、本発明に係る有機発光素子１０は、基板１５上に陽極１４が形成され、その上に有機化合物層として、ホール輸送層１３、発光層１２、電子注入輸送層１６が形成され、さらにその上に陰極１７が形成されている（図１参照）。ここで、本発明の実施例に係る有機発光素子１０を構成する各層は、以下に示す具体的な材料を用いている。 <Example 1 and Example 2, Comparative Example 1 to Comparative Example 4>
As described above, in the organic light emitting device 10 according to the present invention, the anode 14 is formed on the substrate 15, and the hole transport layer 13, the light emitting layer 12, and the electron injection transport layer 16 are formed thereon as the organic compound layer. Further, a cathode 17 is formed thereon (see FIG. 1). Here, the following specific materials are used for each layer constituting the organic light emitting device 10 according to the example of the present invention.

すなわち、基板１５としてガラスを用い、陽極１４としてＡｇとＩＴＯの積層膜を用いる。また、ホール輸送層１３としてＨＴ−１を用い、発光層１２としてＥＭ−１とＥＭ−２の共蒸着層を用い、電子注入輸送層としてＥＴ−１と炭酸セシウムの共蒸着層を用いる。さらに、陰極としてＩＴＯ膜を用いる。   That is, glass is used as the substrate 15 and a laminated film of Ag and ITO is used as the anode 14. Further, HT-1 is used as the hole transport layer 13, a co-deposited layer of EM-1 and EM-2 is used as the light emitting layer 12, and a co-deposited layer of ET-1 and cesium carbonate is used as the electron injecting and transporting layer. Further, an ITO film is used as the cathode.

以下に、実施例１及び実施例２、比較例１乃至比較例４の有機発光素子の製造手順を説明する。   Below, the manufacturing procedure of the organic light emitting element of Example 1, Example 2, and Comparative Examples 1 to 4 will be described.

ガラス基板（コーニング社：１７３７）上に銀を１００ｎｍ、ＩＴＯ膜を２０ｎｍ成膜して透明基板（基板１５）を形成し、さらにフォトリソグラフィー法によりパターニングして、透明電極（陽極１４）を形成する。   A transparent substrate (substrate 15) is formed on a glass substrate (Corning Inc .: 1737) by forming silver with a thickness of 100 nm and an ITO film with a thickness of 20 nm, and then patterning by photolithography to form a transparent electrode (anode 14). .

この透明電極（陽極１４）を、大気圧下でＵＶ−Ｏ3洗浄した後、以下の有機化合物層を１０-4Ｐａの真空チャンバー内で抵抗加熱による真空蒸着法を用いて連続成膜する。その後、スパッタ法を用いてＩＴＯ膜を成膜し、実施例１及び実施例２、比較例１乃至比較例４の有機発光素子１０を得た。 After this transparent electrode (anode 14) is UV-O 3 washed under atmospheric pressure, the following organic compound layers are continuously formed in a vacuum chamber of 10 −4 Pa using a vacuum evaporation method using resistance heating. Thereafter, an ITO film was formed by sputtering, and organic light emitting devices 10 of Examples 1 and 2 and Comparative Examples 1 to 4 were obtained.

ここで、各膜厚等は以下の通りである。   Here, each film thickness etc. are as follows.

ホール輸送層１３は、ＨＴ−１（２０ｎｍ）となっている。また、発光層１２は、ＥＭ−１及びＥＭ−２の共蒸着層（比率ＥＭ−１：ＥＭ−２＝８７：１３）（２０ｎｍ）となっている。電子注入輸送層１６は、ＥＴ−１及び炭酸セシウムの共蒸着層（５０ｎｍ）となっている。   The hole transport layer 13 is HT-1 (20 nm). The light emitting layer 12 is a co-deposited layer of EM-1 and EM-2 (ratio EM-1: EM-2 = 87: 13) (20 nm). The electron injection transport layer 16 is a co-deposited layer (50 nm) of ET-1 and cesium carbonate.

また、実施例１及び実施例２、比較例１乃至比較例４で用いている材料の化学式は、以下の通りである。   The chemical formulas of the materials used in Examples 1 and 2 and Comparative Examples 1 to 4 are as follows.

Figure 2007294901
Figure 2007294901

ここで、ＥＴ−１における炭酸セシウムのドープ濃度は、蒸着工程における蒸着スピードをその濃度に対応するように制御し、所望の濃度に設定した。使用した材料及びその膜厚、作成した素子の特性は、以下の表１に示す通りである。   Here, the doping concentration of cesium carbonate in ET-1 was set to a desired concentration by controlling the vapor deposition speed in the vapor deposition step so as to correspond to the concentration. The materials used, their film thicknesses, and the characteristics of the fabricated devices are as shown in Table 1 below.

Figure 2007294901
Figure 2007294901

＜実施例１＞
電子注入輸送層における炭酸セシウムの濃度を領域ａで０．０１％、領域ｂで５．１０％、領域ｃで０．５％、領域ｄで４．９％として実施例１の有機発光素子を作成した。なお、領域ａ，領域ｂ，領域ｃ，領域ｄは、図１における領域１６ａ，１６ｂ，１６ｃ，１６ｄにそれぞれ対応する（以下の各実施例および各比較例において同様）。 <Example 1>
In the electron injecting and transporting layer, the concentration of cesium carbonate in the region a is 0.01%, the region b is 5.10%, the region c is 0.5%, and the region d is 4.9%. Created. Note that the region a, the region b, the region c, and the region d correspond to the regions 16a, 16b, 16c, and 16d in FIG. 1, respectively (the same applies to the following examples and comparative examples).

実施例１の有機発光素子を２０ｍＡ／ｃｍ2の電流密度で駆動したところ、輝度４６３ｃｄ／ｍ2、駆動電圧３．１Ｖであった。また、実施例１の有機発光素子を２０ｍＡ／ｃｍ2で連続駆動したところ、９０％の輝度まで劣化する時間が約１２７ｈｒであった。同条件で作成した実施例１と同様の有機発光素子を約２００日間常温下で保存した後、２０ｍＡ／ｃｍ2の電流を印加した際の駆動電圧は３．３Ｖであった。 When the organic light emitting device of Example 1 was driven at a current density of 20 mA / cm 2 , the luminance was 463 cd / m 2 and the driving voltage was 3.1 V. Further, when the organic light-emitting device of Example 1 was continuously driven at 20 mA / cm 2 , the time for degradation to 90% luminance was about 127 hr. The organic light emitting device similar to that of Example 1 created under the same conditions was stored at room temperature for about 200 days, and then the driving voltage when a current of 20 mA / cm 2 was applied was 3.3V.

＜比較例１＞
電子注入輸送層における炭酸セシウムの濃度を領域ａで０．０１％、領域ｂで４．９％、領域ｃで４．９％、領域ｄで４．９％として比較例１の有機発光素子を作成した。 <Comparative Example 1>
In the electron injecting and transporting layer, the concentration of cesium carbonate was 0.01% in the region a, 4.9% in the region b, 4.9% in the region c, and 4.9% in the region d. Created.

比較例１の有機発光素子を２０ｍＡ／ｃｍ2の電流密度で駆動したところ、輝度４０２ｃｄ／ｍ2、駆動電圧３．１Ｖであり、実施例１と比較して輝度が低下した。また、比較例１の有機発光素子を２０ｍＡ／ｃｍ2で連続駆動したところ、９０％の輝度まで劣化する時間が約１３５ｈｒであり、実施例１と大きな違いはなかった。同条件で作成した比較例１と同様の有機発光素子を約２００日間常温下で保存した後、２０ｍＡ／ｃｍ2の電流を印加した際の駆動電圧は３．１Ｖであった。 When the organic light emitting device of Comparative Example 1 was driven at a current density of 20 mA / cm 2 , the luminance was 402 cd / m 2 and the driving voltage was 3.1 V, and the luminance was lower than that of Example 1. Further, when the organic light emitting device of Comparative Example 1 was continuously driven at 20 mA / cm 2 , the degradation time to 90% was about 135 hr, which was not significantly different from Example 1. The organic light emitting device similar to Comparative Example 1 prepared under the same conditions was stored at room temperature for about 200 days, and then the driving voltage when a current of 20 mA / cm 2 was applied was 3.1V.

＜比較例２＞
電子注入輸送層における炭酸セシウムの濃度を領域ａで０．００５％、領域ｂで０．５％、領域ｃで０．５％、領域ｄで０．５％として比較例２の有機発光素子を作成した。 <Comparative example 2>
In the electron injecting and transporting layer, the concentration of cesium carbonate is 0.005% in the region a, 0.5% in the region b, 0.5% in the region c, and 0.5% in the region d. Created.

比較例２の有機発光素子を２０ｍＡ／ｃｍ2の電流密度で駆動したところ、輝度５１４ｃｄ／ｍ2、駆動電圧３．５Ｖであり、実施例１と比較して輝度は向上したものの、駆動電圧が上昇した。また、比較例２の有機発光素子を２０ｍＡ／ｃｍ2で連続駆動したところ、９０％の輝度まで劣化する時間が約２０ｈｒであり駆動劣化特性が著しく劣った。同条件で作成した比較例２と同様の有機発光素子を約２００日間常温下で保存した後、２０ｍＡ／ｃｍ2の電流を印加した際の駆動電圧は３．５Ｖであった。 When the organic light emitting device of Comparative Example 2 was driven at a current density of 20 mA / cm 2 , the luminance was 514 cd / m 2 and the driving voltage was 3.5 V. Although the luminance was improved as compared with Example 1, the driving voltage was Rose. Further, when the organic light emitting device of Comparative Example 2 was continuously driven at 20 mA / cm 2 , the deterioration time to 90% was about 20 hours, and the drive deterioration characteristics were extremely inferior. The organic light emitting device similar to Comparative Example 2 prepared under the same conditions was stored at room temperature for about 200 days, and then the driving voltage when a current of 20 mA / cm 2 was applied was 3.5V.

＜実施例２＞
電子注入輸送層における炭酸セシウムの濃度を領域ａで０．０１％、領域ｂで４．８％、領域ｃで０．５％、領域ｄで０．５％として実施例２の有機発光素子を作成した。 <Example 2>
In the electron injecting and transporting layer, the concentration of cesium carbonate in the region a is 0.01%, the region b is 4.8%, the region c is 0.5%, and the region d is 0.5%. Created.

実施例２の有機発光素子を２０ｍＡ／ｃｍ2の電流密度で駆動したところ、輝度４７０ｃｄ／ｍ2、駆動電圧３．５Ｖであった。また実施例２の有機発光素子２を２０ｍＡ／ｃｍ2で連続駆動したところ、９０％の輝度まで劣化する時間が約１１９ｈｒであった。すなわち、実施例２では、比較例１と比較して駆動電圧は上昇したものの、輝度が向上し、耐久特性は比較例１とほぼ同レベルにあった。同条件で作成した実施例２と同様の有機発光素子を約２００日間常温下で保存した後、２０ｍＡ／ｃｍ2の電流を印加した際の駆動電圧は３．５Ｖであった。 When the organic light emitting device of Example 2 was driven at a current density of 20 mA / cm 2 , the luminance was 470 cd / m 2 and the driving voltage was 3.5V. Further, when the organic light emitting device 2 of Example 2 was continuously driven at 20 mA / cm 2, it took about 119 hours to deteriorate to 90% luminance. That is, in Example 2, although the drive voltage was increased as compared with Comparative Example 1, the luminance was improved and the durability characteristics were almost at the same level as Comparative Example 1. The organic light-emitting device similar to that of Example 2 created under the same conditions was stored at room temperature for about 200 days, and then the driving voltage when a current of 20 mA / cm 2 was applied was 3.5V.

＜比較例３＞
電子注入輸送層における炭酸セシウムの濃度を領域ａで０．００５％、領域ｂで０．５％、領域ｃで０．５％、領域ｄで５．１％として比較例３の有機発光素子を作成した。 <Comparative Example 3>
In the electron injecting and transporting layer, the concentration of cesium carbonate was 0.005% in the region a, 0.5% in the region b, 0.5% in the region c, and 5.1% in the region d. Created.

比較例３の有機発光素子を２０ｍＡ／ｃｍ2の電流密度で駆動したところ、輝度４７１ｃｄ／ｍ2、駆動電圧３．１Ｖであった。また、比較例３の有機発光素子を２０ｍＡ／ｃｍ2で連続駆動したところ、９０％の輝度まで劣化する時間が約２５ｈｒであった。すなわち、比較例３では、実施例１と比較して輝度は向上したものの、駆動劣化特性は著しく劣る結果となった。同条件で作成した比較例３と同様の有機発光素子を約２００日間常温下で保存した後、２０ｍＡ／ｃｍ2の電流を印加した際の駆動電圧は３．３Ｖであった。 When the organic light emitting device of Comparative Example 3 was driven at a current density of 20 mA / cm 2 , the luminance was 471 cd / m 2 and the driving voltage was 3.1V. Further, when the organic light-emitting device of Comparative Example 3 was continuously driven at 20 mA / cm 2 , the degradation time to 90% was about 25 hr. That is, in Comparative Example 3, although the luminance was improved as compared with Example 1, the driving deterioration characteristic was remarkably inferior. The organic light emitting device similar to Comparative Example 3 prepared under the same conditions was stored at room temperature for about 200 days, and then the driving voltage when a current of 20 mA / cm 2 was applied was 3.3V.

＜比較例４＞
電子注入輸送層における炭酸セシウムの濃度を領域ａで０．００５％、領域ｂで５．１％、領域ｃで０％、領域ｄで４．８％として比較例４の有機発光素子を作成した。 <Comparative example 4>
The organic light emitting device of Comparative Example 4 was prepared by setting the concentration of cesium carbonate in the electron injecting and transporting layer to 0.005% in the region a, 5.1% in the region b, 0% in the region c, and 4.8% in the region d. .

比較例４の有機発光素子を２０ｍＡ／ｃｍ2の電流密度で駆動したところ、輝度４５９ｃｄ／ｍ2、駆動電圧４．２Ｖであった。また、比較例４の有機発光素子を２０ｍＡ／ｃｍ2で連続駆動したところ、９０％の輝度まで劣化する時間が約５０ｈｒであった。比較例４では、実施例１及び実施例２と比較して、輝度が若干劣るとともに、駆動電圧及び駆動劣化特性が著しく劣る結果となった。同条件で作成した比較例４と同様の有機発光素子を約２００日間常温下で保存した後、２０ｍＡ／ｃｍ2の電流を印加した際の駆動電圧は４．５Ｖであった。 When the organic light emitting device of Comparative Example 4 was driven at a current density of 20 mA / cm 2 , the luminance was 459 cd / m 2 and the driving voltage was 4.2V. Further, when the organic light-emitting device of Comparative Example 4 was continuously driven at 20 mA / cm 2 , the time for degradation to 90% luminance was about 50 hr. In Comparative Example 4, as compared with Example 1 and Example 2, the luminance was slightly inferior, and the driving voltage and the driving deterioration characteristic were remarkably inferior. The organic light-emitting device similar to Comparative Example 4 prepared under the same conditions was stored at room temperature for about 200 days, and then the drive voltage when a current of 20 mA / cm 2 was applied was 4.5V.

＜実施例３＞
実施例３の有機発光素子は、電子注入輸送層としてＥＴ−２と炭酸セシウムの共蒸着層を用いる以外は、実施例１と同様の手順で作成したものである。 <Example 3>
The organic light-emitting device of Example 3 was prepared in the same procedure as in Example 1 except that a co-deposited layer of ET-2 and cesium carbonate was used as the electron injecting and transporting layer.

実施例３の有機発光素子を２０ｍＡ／ｃｍ2の電流密度で駆動したところ、輝度４３１ｃｄ／ｍ2、駆動電圧３．２Ｖであった。また、実施例３の素子を２０ｍＡ／ｃｍ2で連続駆動したところ、９０％の輝度まで劣化する時間が約１２１ｈｒであった。実施例３では、実施例１及び実施例２とほぼ同程度の駆動電圧及び駆動劣化特性とすることができた。同条件で作成した実施例３と同様の有機発光素子を約２００日間常温下で保存した後、２０ｍＡ／ｃｍ2の電流を印加した際の駆動電圧は３．２Ｖであった。 When the organic light emitting device of Example 3 was driven at a current density of 20 mA / cm 2 , the luminance was 431 cd / m 2 and the driving voltage was 3.2 V. Further, when the element of Example 3 was continuously driven at 20 mA / cm 2, it took about 121 hours to deteriorate to a luminance of 90%. In Example 3, the driving voltage and driving deterioration characteristics were almost the same as those in Example 1 and Example 2. An organic light emitting device similar to that of Example 3 created under the same conditions was stored at room temperature for about 200 days, and then a driving voltage when a current of 20 mA / cm 2 was applied was 3.2V.

＜実施例と比較例の比較結果＞
本発明によれば、電子注入輸送層において、膜厚方向で、ドープ濃度が発光層側から順に小、大、小、大となる様に設定することにより、光取り出し効率の低下を招くことなく駆動電圧を低減することができると共に、駆動耐久特性を向上させることができる。 <Comparison result of Example and Comparative Example>
According to the present invention, in the electron injecting and transporting layer, by setting the dope concentration in the film thickness direction from the light emitting layer side in the order of decreasing, increasing, decreasing, and increasing, the light extraction efficiency does not decrease. The driving voltage can be reduced and driving durability characteristics can be improved.

本発明の実施形態に係る有機発光素子の概略構成を示す縦断面模式図である。It is a longitudinal cross-sectional schematic diagram which shows schematic structure of the organic light emitting element which concerns on embodiment of this invention. 本発明の別の実施形態に係る有機発光素子の概略構成を示す縦断面模式図である。It is a longitudinal cross-sectional schematic diagram which shows schematic structure of the organic light emitting element which concerns on another embodiment of this invention.

符号の説明Explanation of symbols

１０ 有機発光素子
１２ 発光層
１３ ホール輸送層
１４ 陽極
１５ 基板
１６ 電子注入輸送層
１７ 陰極 DESCRIPTION OF SYMBOLS 10 Organic light emitting element 12 Light emitting layer 13 Hole transport layer 14 Anode 15 Substrate 16 Electron injection transport layer 17 Cathode

Claims (6)

互いに対向して配置されている陽極および陰極と、前記陽極と前記陰極の間に形成されている発光層と、前記陰極と前記発光層の間に形成されており、前記陰極および前記発光層に接している電子注入輸送層と、を有し、
前記電子注入輸送層は、電子輸送材料と、電子注入ドーパント材料としてアルカリ金属あるいはアルカリ金属化合物、を含む有機発光素子において、
前記電子注入輸送層は、前記発光層側から順に、前記電子注入ドーパント材料の濃度の異なる第１領域、第２領域、第３領域、を有しており、
前記第２領域の前記電子注入ドーパント材料の濃度は、前記第１領域および前記第３領域の前記電子注入ドーパント材料の濃度よりも高いことを特徴とする有機発光素子。 An anode and a cathode disposed opposite to each other, a light emitting layer formed between the anode and the cathode, and formed between the cathode and the light emitting layer. An electron injecting and transporting layer in contact,
The electron injecting and transporting layer includes an electron transporting material and an alkali metal or an alkali metal compound as an electron injecting dopant material.
The electron injecting and transporting layer has, in order from the light emitting layer side, a first region, a second region, and a third region having different concentrations of the electron injecting dopant material,
The organic light emitting device, wherein the concentration of the electron injection dopant material in the second region is higher than the concentration of the electron injection dopant material in the first region and the third region. 前記電子注入ドーパント材料の濃度は、前記第１領域では０．０１重量％以下であり、前記第２領域では４重量％以上６重量％以下であり、前記第３領域では０．１重量％以上１重量％以下であることを特徴とする請求項１に記載の有機発光素子。   The concentration of the electron injection dopant material is 0.01 wt% or less in the first region, 4 wt% or more and 6 wt% or less in the second region, and 0.1 wt% or more in the third region. The organic light-emitting device according to claim 1, wherein the content is 1% by weight or less. 前記電子注入層は、前記第３領域と前記陰極との間に第４領域を有しており、
前記第４領域の前記電子注入ドーパント材料の濃度は、前記第３領域の前記電子注入ドーパント材料の濃度よりも高いことを特徴とする請求項１または請求項２のいずれか１項に記載の有機発光素子。 The electron injection layer has a fourth region between the third region and the cathode,
3. The organic material according to claim 1, wherein a concentration of the electron injection dopant material in the fourth region is higher than a concentration of the electron injection dopant material in the third region. Light emitting element. 前記電子注入ドーパント材料の濃度は、前記第４領域では４重量％以上６重量％以下であることを特徴とする請求項３に記載の有機発光素子。   4. The organic light emitting device according to claim 3, wherein the concentration of the electron injection dopant material is 4 wt% or more and 6 wt% or less in the fourth region. 前記電子注入輸送層の前記第２領域の厚みは、５ｎｍ以上２０ｎｍ以下であることを特徴とする請求項１乃至請求項４のいずれか１項に記載の有機発光素子。   5. The organic light-emitting element according to claim 1, wherein a thickness of the second region of the electron injecting and transporting layer is 5 nm or more and 20 nm or less. 前記電子注入ドーパント材料は炭酸セシウムであることを特徴とする請求項１乃至請求項５のいずれか１項に記載の有機発光素子。   The organic light-emitting device according to claim 1, wherein the electron-injecting dopant material is cesium carbonate.
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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101223615B1 (en) 2010-12-31 2013-01-17 서울대학교 산학협력단 Inverted organic light-emitting diode and flat display device comprising the same
JP2013539182A (en) * 2010-09-06 2013-10-17 エルジー・ケム・リミテッド Organic electronic device substrate and organic electronic device including the same
JP2015053493A (en) * 2008-10-01 2015-03-19 エルジー・ケム・リミテッド Organic light emitting element and method of manufacturing the same
JP2016115717A (en) * 2014-12-11 2016-06-23 株式会社Ｊｏｌｅｄ Organic el element and method of manufacturing organic el element

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4898560B2 (en) * 2006-06-23 2012-03-14 キヤノン株式会社 Organic light emitting device
US20080278072A1 (en) * 2007-04-30 2008-11-13 Lg Chem, Ltd. Organic light emitting device and method of producing the same
KR101045264B1 (en) * 2008-09-09 2011-06-29 네오뷰코오롱 주식회사 Display apparatus, mobile device having the same and display control method

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003234196A (en) * 2002-01-31 2003-08-22 Eastman Kodak Co Organic electric field light emitting device
JP2003272868A (en) * 2002-03-20 2003-09-26 Denso Corp Organic el element

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH10270171A (en) 1997-01-27 1998-10-09 Junji Kido Organic electroluminescent element
JP4486713B2 (en) 1997-01-27 2010-06-23 淳二 城戸 Organic electroluminescent device
JP4076769B2 (en) 2000-12-28 2008-04-16 株式会社半導体エネルギー研究所 Light emitting device and electric appliance
SG138466A1 (en) * 2000-12-28 2008-01-28 Semiconductor Energy Lab Luminescent device
CN101355141B (en) * 2001-06-15 2012-02-29 佳能株式会社 Organic electroluminescent device
JP2005063910A (en) 2003-08-20 2005-03-10 Canon Inc Organic light emitting element and its manufacturing method
TWI382079B (en) * 2004-07-30 2013-01-11 Sanyo Electric Co Organic electric field light-emitting element and organic electric field light-emitting display device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003234196A (en) * 2002-01-31 2003-08-22 Eastman Kodak Co Organic electric field light emitting device
JP2003272868A (en) * 2002-03-20 2003-09-26 Denso Corp Organic el element

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2015053493A (en) * 2008-10-01 2015-03-19 エルジー・ケム・リミテッド Organic light emitting element and method of manufacturing the same
US9587172B2 (en) 2008-10-01 2017-03-07 Lg Display Co., Ltd. Organic light-emitting diode and method of manufacturing the same
JP2013539182A (en) * 2010-09-06 2013-10-17 エルジー・ケム・リミテッド Organic electronic device substrate and organic electronic device including the same
US9257675B2 (en) 2010-09-06 2016-02-09 Lg Chem, Ltd. Substrate for an organic electronic device and an organic electronic device comprising the same
KR101223615B1 (en) 2010-12-31 2013-01-17 서울대학교 산학협력단 Inverted organic light-emitting diode and flat display device comprising the same
JP2016115717A (en) * 2014-12-11 2016-06-23 株式会社Ｊｏｌｅｄ Organic el element and method of manufacturing organic el element

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